Question

#include <stdio.h>
int arr[] = {1, 2,3,4,5};
#define TOT (sizeof(arr)/sizeof(arr[0]))

int main()
{
    int d = -1, x = 0;
    if(d<= TOT){
       x = arr[4];
       printf("%d", TOT);
    }
    printf("%d", TOT);
}

TOT has the value 5 but the if condition is failing..why is that?

Answer 1

Because there are “the usual arithmetic conversions” at work for the if.

The sizeof operator returns an unsigned type … and d is converted to unsigned making it greater than the number of elements in arr.

Try

#define TOT (int)(sizeof(arr)/sizeof(arr[0]))

or

 if(d<= (int)TOT){